Are you a snorkeller, diver, fisher or beach-walker, or do you play in the ocean on holidays? I'm searching for sea turtles all around the bottom half of Australia and maybe you've seen one. To date there has been very little field work done to survey sea turtles below their commonly accepted tropical habitat, but in NSW at least, turtles are regularly seen all along the coastline.
During this survey I hope to uncover these answers as I gather more and more evidence of resident sea turtles in sub-tropical waters and early results show them residing as far south as Jervis Bay at around 35 degrees S. Here, a local dive operator has been recording her sea turtle sightings for almost 17 years. This is very exciting news and complements the some 200+ sightings across the NSW coastline I have already gathered through field surveys and literature reviews. Contrary to commonly accepted distribution maps, hawksbill turtles have been recorded well further south than the southerly most range. Take the NOAA map below for example, most maps of hawksbill turtle distributions abruptly stop at the the NSW/Qld border, however records during this project place healthy resident hawksbills as far south as Lord Howe Island at 31 degrees S.
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http://www.nmfs.noaa.gov/pr/pdfs/rangemaps/hawksbill_turtle.pdf |
Why is this important? Turtles are a protected species under Australian law, and meet the requirements needed for further protection under other treaties such as the Migratory Species Act which serves to protect these animals across their life history, not just when they turn up in protected areas (which may be insufficient anyway given they were declared long before comprehensive seafloor data was available). All life history phases of a sea turtle have been recorded in NSW, with the exception of courting behaviour which has yet to be confirmed but has been reported often at some localities. Recent research suggests that Northern NSW beaches and their (already proven) suitable nesting habitat may be the saving grace of the many loggerhead turtles nesting at the massive Mon Repos colony in Queensland, many of which could become climate refugees. Considering that loggerhead turtles already nest in Northern NSW and pressures on nesting colonies to the north are only increasing, an increase in loggerhead nesting behaviour in that region seems likely in the future. But how will we know if there is an increase in nesting or foraging numbers of any species if we don't have a grasp on the current situation?
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| Green sea turtle foraging in the Cape Byron Marine Park. |
Given this growing mountain of evidence, it is erroneous to suggest that sea turtles, particularly greens and hawksbills, are "tropical" species when both species are being recorded with regularity in sub-tropical waters. Time to re-write some of those text books perhaps and remind the state government of their legal responsibility to act to protect and conserve the species.
